1. Field of the Invention
This invention relates to an expansible antenna apparatus adapted to be mounted on a spacecraft such as an artificial satellite and constructed in outer space.
2. Description of the Related Art
Research and development carried out in the field of space technology have resulted in the creation of the expansible antenna apparatus comprising an antenna reflection mirror which is folded while on earth and unfolded in outer space, since the former configuration is required for ease of launching into space. A proposed expansible antenna apparatus has an antenna reflection mirror formed of a flexible conductive film, which is attached to an expansible mirror-supporting member. In such a case, the mirror surface accuracy of an antenna reflection mirror must be kept in a range of about 1/50 to 1/100 of the wavelength used (the r.m.s. value of the entire mirror surface).
Hence, it is essential that the expansible antenna be able to fold and unfold with high reliability and accuracy. In addition, expansion errors in the case of the antenna reflection mirror and accuracy errors in the mirror surface, both stemming from heat deformation caused by changes in temperature in the outer space environment must be controlled and the required mirror surface accuracy maintained.
However, since, in the type of expansible antenna apparatus as described above, components such as the mirror-supporting member are remote-controlled, this results in various troubles.
For example, the above antenna apparatus requires the provision of a relatively large number of connection cables between the power source system and actuators for unfolding the antenna apparatus and adjusting the mirror surface. Therefore, when the mirror-supporting member is in the process of being folded or unfolded, there is a possibility of the connection cables being interwound with the mirror-supporting member and the like, making it difficult or impossible to fold or unfold the antenna and thus adversely affecting the apparatus' performance.